Plastic

The invention: The first totally synthetic thermosetting plastic,

which paved the way for modern materials science.

The people behind the invention:

John Wesley Hyatt (1837-1920), an American inventor

Leo Hendrik Baekeland (1863-1944), a Belgian-born chemist,

consultant, and inventor

Christian Friedrich Schönbein (1799-1868), a German chemist

who produced guncotton, the first artificial polymer

Adolf von Baeyer (1835-1917), a German chemist

Exploding Billiard Balls

In the 1860’s, the firm of Phelan and Collender offered a prize of

ten thousand dollars to anyone producing a substance that could

serve as an inexpensive substitute for ivory, which was somewhat

difficult to obtain in large quantities at reasonable prices. Earlier,

Christian Friedrich Schönbein had laid the groundwork for a breakthrough

in the quest for a new material in 1846 by the serendipitous

discovery of nitrocellulose, more commonly known as “guncotton,”

which was produced by the reaction of nitric acid with cotton.

An American inventor, John Wesley Hyatt, while looking for a

substitute for ivory as a material for making billiard balls, discovered

that the addition of camphor to nitrocellulose under certain

conditions led to the formation of a white material that could be

molded and machined. He dubbed this substance “celluloid,” and

this product is now acknowledged as the first synthetic plastic. Celluloid

won the prize for Hyatt, and he promptly set out to exploit his

product. Celluloid was used to make baby rattles, collars, dentures,

and other manufactured goods.

As a billiard ball substitute, however, it was not really adequate,

for various reasons. First, it is thermoplastic—in other words, a material

that softens when heated and can then be easily deformed or

molded. It was thus too soft for billiard ball use. Second, it was

highly flammable, hardly a desirable characteristic. Awidely circulated, perhaps apocryphal, story claimed that celluloid billiard balls

detonated when they collided.

Truly Artificial

Since celluloid can be viewed as a derivative of a natural product,

it is not a completely synthetic substance. Leo Hendrik Baekeland

has the distinction of being the first to produce a completely artificial

plastic. Born in Ghent, Belgium, Baekeland emigrated to the

United States in 1889 to pursue applied research, a pursuit not encouraged

in Europe at the time. One area in which Baekeland hoped

to make an inroad was in the development of an artificial shellac.

Shellac at the time was a natural and therefore expensive product,

and there would be a wide market for any reasonably priced substitute.

Baekeland’s research scheme, begun in 1905, focused on finding

a solvent that could dissolve the resinous products from a certain

class of organic chemical reaction.

The particular resins he used had been reported in the mid-

1800’s by the German chemist Adolf von Baeyer. These resins were

produced by the condensation reaction of formaldehyde with a

class of chemicals called “phenols.” Baeyer found that frequently

the major product of such a reaction was a gummy residue that was

virtually impossible to remove from glassware. Baekeland focused

on finding a material that could dissolve these resinous products.

Such a substance would prove to be the shellac substitute he sought.

These efforts proved frustrating, as an adequate solvent for these

resins could not be found. After repeated attempts to dissolve these

residues, Baekeland shifted the orientation of his work. Abandoning

the quest to dissolve the resin, he set about trying to develop a resin

that would be impervious to any solvent, reasoning that such a material

would have useful applications.

Baekeland’s experiments involved the manipulation of phenolformaldehyde

reactions through precise control of the temperature

and pressure at which the reactions were performed. Many of these

experiments were performed in a 1.5-meter-tall reactor vessel, which

he called a “Bakelizer.” In 1907, these meticulous experiments paid

off when Baekeland opened the reactor to reveal a clear solid that

was heat resistant, nonconducting, and machinable. Experimentation proved that the material could be dyed practically any color in

the manufacturing process, with no effect on the physical properties

of the solid.

Baekeland filed a patent for this new material in 1907. (This patent

was filed one day before that filed by James Swinburne, a British electrical engineer who had developed a similar material in his

quest to produce an insulating material.) Baekeland dubbed his new

creation “Bakelite” and announced its existence to the scientific

community on February 15, 1909, at the annual meeting of the American

Chemical Society. Among its first uses was in the manufacture

of ignition parts for the rapidly growing automobile industry.

Impact

Bakelite proved to be the first of a class of compounds called

“synthetic polymers.” Polymers are long chains of molecules chemically

linked together. There are many natural polymers, such as cotton.

The discovery of synthetic polymers led to vigorous research

into the field and attempts to produce other useful artificial materials.

These efforts met with a fair amount of success; by 1940, a multitude

of new products unlike anything found in nature had been discovered.

These included such items as polystyrene and low-density

polyethylene. In addition, artificial substitutes for natural polymers,

such as rubber, were a goal of polymer chemists. One of the results

of this research was the development of neoprene.

Industries also were interested in developing synthetic polymers

to produce materials that could be used in place of natural fibers

such as cotton. The most dramatic success in this area was achieved

by Du Pont chemist Wallace Carothers, who had also developed

neoprene. Carothers focused his energies on forming a synthetic fiber

similar to silk, resulting in the synthesis of nylon.

Synthetic polymers constitute one branch of a broad area known

as “materials science.” Novel, useful materials produced synthetically

from a variety of natural materials have allowed for tremendous

progress in many areas. Examples of these new materials include

high-temperature superconductors, composites, ceramics, and

plastics. These materials are used to make the structural components

of aircraft, artificial limbs and implants, tennis rackets, garbage

bags, and many other common objects.